In June 1993 Pertamina made a revision of the 1985 Indonesian gas resources published by the Committee for Centenial Oil and Gas Activity in Indonesia authored by Suardy and Taruno. The purpose of this revision is to restate the gas potential anticipating its role on the energy policy in the Second Long Term National Development (PJPT-II). The assessment used the known 60 sedimentary basins as a basis for the calculation. The figures obtained were grouped into three categories considering degree of assurance i.e. recoverable reserves, hypothetical resources and speculative resources. The result indicates that for the status June 1993 the remaining recoverable gas reserves is 104.7 TCF, the hypothetical resources in-place 234.5 TCF and the speculative resources in-place 212.4 TCF. The above 1985 publication declared initial reserves of 307.6 TCF and resources of 216.8 TCF. Most of the basins located in the eastern Indonesia have small speculative resources because of the low chance factors used for calculating the resources. The basin types determining the factors such as oceanic margin, transitional subduction fore arc and transitional collision brought about pessimistic figures. Future additional data might create new basinal models which subsequently improve the figures. The paper reviews the process and the methodologies including the geologic assumptions used for assigning the reserves and the resources of each category. Vision on expected activities within 25 years ahead to change the resources into the reserves is also discussed. Some 203,000 kms of seismic surveys and 746 drillings are necessary to be carried out for the purpose to generate additional gas reserves of 54.5 TCF.
Authors : F.X. Sujanto, Lukman Kartanegara, Yanto R Sumantri & L. Gultom